Workflow: an Haskell package for transparent support of interruptible computations

A month ago i uploaded the package Workflow to hackage, the repository of Haskell libraries. I added an hopefully self suficient documentations and examples.

Here follows a few remarks, a simple example and a more sophsticated example:

The main features are: Transparent state logging trough a monad transformer: step :: m a -> Workflow m a. Resume the computation state after an accidental o planned program shutdown (restartWorkflows). Event handling (waithFor, waitForData). Monitoring of workflows with state change display and other auxiliary features. Communications with other processes including other workflows trough persistent data objects, inspecttion of intermediate workflow results , Queues so that no data is lost due to shutdowns Here is a complete example: This is a counter that shows a sequence of numbers, one a second: module Main where import Control.Concurrent(threadDelay) import System.IO (hFlush,stdout) count n= putStr (show n ++ ) >> hFlush stdout >> threadDelay 1000000 >> count (n+1) main= count 0 This is the same program, with the added feature of remembering the last count after interrupted: module Main where import Control.Workflow import Control.Concurrent(threadDelay) import System.IO (hFlush,stdout) mcount n= step $ putStr (show n ++ ) >> hFlush stdout >> threadDelay 1000000 >> mcount (n+1) main= do registerType :: IO () registerType :: IO Int let start= 0 :: Int startWF count start [(count, mcount)] :: IO () This is the execution log: Worflow-0.5.5demos>runghc sequence.hs 0 1 2 3 4 5 6 7 sequence.hs: win32ConsoleHandler sequence.hs: sequence.hs: interrupted Worflow-0.5.5demos> Worflow-0.5.5demos>runghc sequence.hs 7 8 9 10 11 ....

Here is the complete documentation iof the package

And here is a more sophisticated example, at pastebin.org. The code is also documented.